Electronic apparatus and hard disk drive housing apparatus

ABSTRACT

A system for mounting a hard disk drive inside an electronic apparatus in such a way that the hard disk drive is isolated from vibration and noise and heat generated by the hard disk dive is radiated to a cover of the electronic apparatus to prevent overheating. A foam heat transmission sheet is placed between the hard disk drive cover and an outer casing that is mounted to the electronic apparatus and far-infrared ray transmitting and receiving sheets are attached to the outside of the outer casing and to the inside of the cover of the electronic apparatus to transmit heat from the hard disk drive to the exterior of the apparatus.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electronic apparatus and a hard disk drive housing apparatus, and particularly to an electronic apparatus and a hard disk drive housing apparatus in which radiated heat and a noise from an electronic apparatus and a hard disk drive housing apparatus can be absorbed so that the electronic apparatus and the hard disk drive housing apparatus can be prevented from being affected by shock from the outside.

2. Description of the Related Art

A known case main body for accommodating therein a drive unit rotating at high speed within a hard disk drive (HDD) has had an airtight property in order to prevent hearing a noise generated when the drive unit is rotated and vibrated. Such an airtight case main body encounters problems in that, because it has no holes and thus no air convection, it accumulates heat and cannot sufficiently radiate heat. To solve the above-mentioned problems, cited patent reference 1 has disclosed an HDD housing structure in which two problems of heat radiation and absorption of vibration can be solved effectively while the airtight property can be maintained.

FIG. 1 of the accompanying drawings is a schematic perspective view showing a HDD housing structure disclosed in the cited patent reference 1.

As shown in FIG. 1, the above-described cited patent reference 1 discloses a housing structure for housing a HDD 7 in which a hard disk drive unit and the like are housed within a flat case 1 of which outward appearance is substantially a rectangular solid and in which noise absorption members 4 a, 4 b, 4 c and 4 d are provided within the case 1. As shown in FIG. 1, the case 1 is composed of a case lid 2 and a box-like case main body 3 with the case 2 mounted to an open bottom portion thereof. Noise absorption members 4 a, 4 b, 4 c and 4 d, each of which has a predetermined thickness, are disposed along the inner wall portion around the case main body 3. A heat radiation plate 5 is located on the inside of the top portion 3 a of the case main body 3 and a drive unit is located between supporting members 6L and 6R erected from the heat radiation plate 5 to the inside of the case main body 3. In order to enable the heat radiation plate 5, the supporting members 6L, 6R and the case lid 2 to form a heat radiation structure which contacts with the drive unit to radiate heat from the drive unit, the case lid 2, the case main body 3, the heat radiation plate 5 and the supporting members 6L, 6R are made of aluminum or aluminum alloy.

According to this arrangement, the noise absorption members 4 a, 4 b, 4 c and 4 d can absorb a vibration noise and they can also decrease leakage of a noise to the outside. In addition, the case lid 2, the case main body 3, the heat radiation plate 5 and the supporting members 6L, 6R are made of material having excellent heat transmission property and hence heat radiation effect of the drive unit can be exhibited.

As shown in FIG. 1, the noise absorption members 4 a, 4 b, 4 c and 4 d are made of a sponge-like soft synthetic resin or a natural rubber and a part of the noise absorption members 4 a, 4 b, 4 c and 4 d can kept its position in the state in which it is held between the inner wall surface of the case main body 3 and the supporting members 6L, 6R. Also, the heat radiation plate 5 is attached to the inner surface of the case lid 2 through a member with high heat transmission property and cushion property, for example, a square plate member 8 made of an adhesive synthetic resin commercially available under the trade name of “SORBOTHANE” and this heat radiation plate 5 is brought in contact with the drive unit of the HDD 7. A second heat radiation plate 5 a is provided between the case lid 2 and the heat radiation plate 5 and it is brought in contact with the case lid 2 through the second square member 8 a and the noise absorption member 4 d. Accordingly, heat is transmitted from the heat radiation plate 5 a to the case lid 2 by the second square plate member 8 a with the high heat transmission property and the cushion property.

Further, a cited patent reference 2 has disclosed a structure to completely house a hard disk (HD) into a box made of a noise absorption material 4 as an attachment structure in which a noise generated from the HDD 7 can be decreased and in which heat radiation efficiency can be improved.

FIG. 2 is a cross-sectional side view showing the HDD 7 disclosed as an example of the related art of the cited patent reference 2. This related-art example has a silent disk drive structure that has been described in the specification of U.S. Pat. No. 5,510,954. The related-art example is composed of the noise absorption member 4 provided in the periphery of the HDD 7, a noise insulation case 15 provided in a heat sink 9 and a heat transmission path 10.

Specifically, as shown in FIG. 2, a disk drive 11 of the HDD 7 is enclosed by a heat transmission and vibration absorption member 12 and a metal case 13 of the HDD 7. The noise absorption member 4 is provided between the metal case 13 and the noise insulation case 15 and the metal case 13 and the heat sink 9 is connected by the heat transmission path 10.

According to the arrangement of the HDD 7 described in the above-mentioned cited patent reference 1, the noise absorption members 4 a to 4 d and the two heat radiation plates 3 and 3 a are housed within the case main body 3 and the case lid 2 comprising the case 1 and there arises a problem, in which the case 1 of the HDD 7 becomes large in size.

Also, according to the arrangement of the HDD 7 described in the above-mentioned cited patent reference 2, the following problems arise in addition to the problem encountered with the above-mentioned cited patent reference 1.

Since the HDD 7 containing the HD (disk drive 11) generates a large amount of heat and it should be kept under a certain circumstance temperature in order to maintain function reliability, when the HDD 7 is completely housed within the box of the noise insulation case 15 covered with the noise absorption member 4, heat radiation effect becomes a serious problem depending upon the surrounding air circumstance conditions. Although heat is radiated by the heat sink 9 located outside the noise insulation case 15 through the heat transmission path 10 in the cited patent reference 2, in the case of the HDD which generates a large amount of heat, there is a limit to generate heat by using only the heat sink 9 and hence it becomes difficult to keep the HD within the HDD 7 and the head under a constant circumstance temperature.

Also, in order to increase heat radiation efficiency, the heat sink 9 should become large in size and hence the space is increased, which makes the whole of the HDD 7 become larger in size. When external force such as shock is applied to such heat sink 9 from the outside, the disk drive of the HDD 7 is directly vibrated and problems arise, in which the pickup head and the like will be broken.

Further, as a condition under which the HDD 7 is mounted on the electronic apparatus, there is prescribed that the HDD 7 should be mounted with a constant distance from other components to be mounted. The reason for this is that an atmospheric pressure within the metal case 13 of the HDD 7 should be kept constant and breathing holes should be closed so that stress may not be applied to the HD. In the arrangement shown in FIG. 2, since the heat transmission path 10 directly comes in contact with the HDD 7, a problem arises, in which function reliability of the disk drive 11 will be affected.

[Cited patent reference 1]: Official gazette of Japanese laid-open patent application No. 2002-74929

[Cited patent reference 2]: Official gazette of Japanese laid-open patent application No. 11-66832

SUMMARY OF THE INVENTION

In view of the aforesaid aspect, it is an object of the present invention to provide an electronic apparatus and a HDD in which the HDD can be protected from shock when the electronic apparatus and a heat radiation device of the HDD are shocked from the outside.

It is another object of the present invention to provide an electronic apparatus and a HDD in which heat generated from the HDD can be radiated efficiently and in which highly-reliable hard disk function can be maintained by decreasing a seek noise generated when a pickup head within the HDD frequently seeks a target track.

According to an aspect of the present invention, there is provided an electronic apparatus which is comprised of a hard disk drive for recording and/or reproducing a signal, a heat transmission portion for receiving heat generated from the hard disk drive and transmitting received heat, a heat radiation portion for radiating transmitted heat and an arrangement in which the hard disk drive is attached to a fixed portion of the electronic apparatus through an elastic material, the heat radiation portion is attached to the fixed portion of the electronic apparatus without the elastic material and heat is transmitted to the hard disk drive, the heat radiation portion and the heat transmission portion through two opposing surfaces of far-infrared ray transmitting and receiving member distant from each other by a predetermined distance.

According to other aspect of the present invention, in the above-mentioned electronic apparatus, the electronic apparatus is comprised of a box type outer casing in which an inner casing of the hard disk drive is housed through a noise insulation member or a vibration isolation member, a chassis for holding the outer casing by a shock-absorbing member and a cover for covering the chassis, wherein heat from the inner casing of the hard disk drive is transmitted to the outer casing and the thus transmitted heat is radiated through the far-infrared ray transmitting and receiving member disposed on the outer surface of the outer casing to the cover with or without the far-infrared ray transmitting and receiving member being disposed.

In accordance with a further aspect of the present invention, there is provided a hard disk drive housing apparatus which is comprised of a box type outer casing in which a hard disk drive is housed through a noise insulation member or a vibration isolation member, a chassis for holding the outer casing by a shock-absorbing member, a cover for covering the chassis, a heat transmission portion disposed on a top of the inner casing of the hard disk drive housing apparatus. The hard disk drive housing apparatus further comprises a far-infrared ray transmitting and receiving member disposed on the outer surface of the outer casing and a heat radiation portion with or without the far-infrared ray transmitting and receiving member disposed at the position opposing to and spaced apart from the outer surface of the outer casing, wherein heat of the inner casing is transmitted to the outer casing through the heat transmission portion and heat within the inner casing is radiated to the heat radiation portion.

According to the above-mentioned HDD and electronic apparatus of the present invention, there can be obtained the HDD and the electronic apparatus in which the HDD can be protected from being shocked when the shock is applied the electronic apparatus and the heat radiation means of the HDD from the outside.

According to the electronic apparatus and the HDD of the present invention, there can be obtained the electronic apparatus and the HDD in which heat generated from the HDD can be efficiently radiated and a seek noise generated when the pickup head within the HDD frequently seeks a target track can be decreased so that reliability of hard disk function can be maintained.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a hard disk drive (HDD) and to which reference will be made in explaining a noise insulation unit according to the related art:

FIG. 2 is a cross-sectional side view of a hard disk drive shown in an example of the related art and to which reference will be made in explaining a noise insulation unit according to the related art;

FIG. 3 is a perspective view showing an overall arrangement of a recorder according to an embodiment of the present invention with its cover being removed;

FIG. 4 is a plan view showing a chassis of the recorder shown in FIG. 3;

FIG. 5 is a perspective view showing the chassis of the recorder according to the present invention and to which reference will be made in explaining the state in which an air current is disturbed by cooling fans;

FIG. 6 is a plan view of the HDD and shows schematically the layout of the cooling fans for use with the recorder according to the present invention;

FIG. 7 is a perspective view of an outward appearance showing the attached state of a HDD drive unit for use with the recorder according to the present invention;

FIG. 8 is a cross-sectional view taken along the line VIII—VIII in FIG. 7 and to which reference will be made in explaining a heat radiation method in the HDD for use with the recorder according to the present invention;

FIG. 9 is an exploded perspective view showing the state in which the HDD for use with the recorder according to the present invention is attached to an outer casing;

FIG. 10 is a perspective view showing a film sheet for use with the recorder according to the present invention;

FIG. 11 is a perspective view showing the state in which an elastic member and an earth ground member are attached to the film sheet of FIG. 10;

FIGS. 12A and 12B are schematic diagrams showing the state in which the HDD is assembled on the outer casing for use with the recorder according to the present invention, respectively;

FIG. 12C is a schematic diagram showing a portion D in FIG. 12B in an enlarged-scale;

FIGS. 13A and 13B are perspective views used to explain a pull-out member to pull out the HDD from the outer casing of the recorder according to the present invention, respectively;

FIG. 14 is a schematic cross-sectional side view used to explain the state in which the HDD is pulled out of the outer casing of the recorder according to the present invention;

FIG. 15 is a flowchart to which reference will be made in explaining a method for controlling a plurality of cooling fans according to the present invention;

FIGS. 16A and 16B are respectively cross-sectional side views similar to FIG. 8 and illustrate a main portion of another embodiment of the present invention and to which reference will be made in explaining a method for radiating heat from the HDD according to the present invention; and

FIG. 17 is a perspective view similar to FIG. 10 and shows a film sheet for use with the recorder according to another embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

An electronic apparatus and a hard disk drive (HDD) according to an embodiment of the present invention will hereinafter be described with reference to FIGS. 3 to 15 on the basis of a recorder including a plurality of recording and/or reproducing drive units, by way of example.

FIG. 3 is a perspective view showing an overall arrangement of a recorder according to the present invention with its cover being removed; FIG. 4 is a plan view showing a chassis of the recorder; FIG. 5 is a perspective view of the chassis of the recorder and to which reference will be made in explaining the state in which air is sent by ventilators; FIG. 6 is a schematic plan view used to explain the state in which air is sent by ventilators; FIG. 7 is a perspective view used to explain the state in which a HDD is attached to a HDD drive unit of the recorder: FIG. 8 is a cross-sectional view taken along the line VIII—VIII in FIG. 7; FIG. 9 is an exploded perspective view showing the state in which the HDD is attached to the outer casing; FIG. 10 is a perspective view showing a film sheet; FIG. 11 is a perspective view showing the state in which an elastic member and an earth ground member are attached to the film sheet; FIGS. 12A, 12B and 12C are schematic diagrams used to explain the state in which the HDD is assembled to the outer casing, respectively; FIGS. 13A, 13B and FIG. 14 are schematic perspective views and a schematic cross-sectional side view used to explain the state in which the HDD is pulled out of the outer casing, respectively; and FIG. 15 is a flowchart to which reference will be made in explaining a method of controlling a plurality of cooling fans according to the present invention.

As shown in FIG. 3, a recorder 20 used as an electronic apparatus includes a main casing 25 composed of a chassis 21 having a substantially U-like cross-section made of a suitable metal such as aluminum, a panel 22 and a back plate 23 disposed on the front side and the back side of the chassis 21 and a cover (not shown in FIG. 3 but shown in FIG. 8) 24 having a substantially U-like cross-section.

The chassis 21 of the recorder 20 has vent holes bored thereon to take air into the recorder 20. The chassis 21 has a ventilator 26 a (see FIGS. 3 and 6) and ventilators 26 b, 26 c (see FIGS. 4 and 5) formed thereon, and a cover 24 also have suitable vent holes bored thereon. A power supply unit 27 is disposed on the left front side of the major surface of the chassis 21, a DVD drive unit 28 is disposed on the central front side of the chassis 21 and a HDD drive unit 29 is disposed on the right front side of the major surface of the chassis 21. A partition plate 30 is disposed at substantially the central position of the chassis 21 so as to become parallel to the panel 22 and the back plate 23. A tuner unit 31 is disposed at the right back side between the partition plate 30 and the back plate 23 on the chassis 21. A computer unit (CPU (central processing unit)) 34 with heat radiation members such as a second cooling fan 35 with a relatively small capacity and a heat sink 33 is disposed at the central back side in the state in which they are inclined in the longitudinal direction of the partition plate 30. A first cooling fan 32 with a relatively large capacity is disposed on the left-hand side of the back plate 23. The panel 22 has at least on its front formed a tray slot 37 of a size large enough to load and unload a tray 36 which can be freely inserted into and ejected from the DVD drive unit 28. Although not shown, various kinds of operation devices are disposed on the front of the panel 22.

As shown in a plan view of FIG. 4 and a perspective view of FIG. 5 showing the chassis 21 with its panel 22 being removed, an open air detection sensor 38 for detecting a temperature of the open air is provided in the vicinity of the ventilator 26 c bored on the chassis 21 of the front portion of the HDD drive unit 29. A CPU sensor 39 for controlling a temperature of the CPU 34 is located within the CPU 34. In FIG. 4, reference numerals 40 denote rubber leg members comprising shock absorbing devices.

In the recorder 20 according to this embodiment, as shown in FIG. 5, the open air 42 taken from the above-described respective ventilators 26 a, 26 b and 26 c is absorbed by the second cooling fan 35 through opening holes 41 bored through the partition plate 30 so that the open air 42 is forcedly air-cooled behind the back plate 23 by the first cooling fan 32 while the heat sink 33 of the CPU 34 is being air-cooled.

When the above-mentioned second cooling fan 35 is inclined with a proper inclination angle relative to the opening holes 41 bored through the partition plate 30, the air-cooling effect for air-cooling the heat sink 33 of the CPU 34 can be enhanced. The reason for this will be described with reference to the schematic plan view of FIG. 6. In FIG. 6, elements and parts identical to those of FIG. 5 are denoted by identical reference numerals and therefore need not be described. FIG. 6 is a plan view schematically showing the case in which the ventilation method shown in FIG. 5 is applied to the inside of a substantially flat rectangular solid-like inner metal casing 43 comprising an enclosure of a HDD 45 which will be described later on.

The open air 42 taken into the inner casing 43 from the ventilators 26 a, 26 d bored through the left and right side walls of the inner casing 43 and the ventilator 26 c bored through the front surface of the inner casing 43 is absorbed by the second cooling fan 35 and sent to the heat sink 33 located at the front surface of the second cooling fan 35 with a proper inclination angle. In the case of FIG. 6, the second cooling fan 35 is not fixed to the chassis 21 with a proper inclination angle but the heat sink 33 is inclined with a proper inclination angle relative to the second cooling fan 35, which has a relative relationship with the case of FIG. 5. Thus, it can be considered that the arrangement shown in FIG. 6 is identical to that shown in FIG. 5.

A heat generating device such as the CPU 34 is located under the heat sink 33. The first cooling fan 32 is attached to the back plate 23 of the inner casing 43 to exhaust the heated air from the inner casing 43 through the first cooling fan 32 to the outside after the open air 42 has passed through fins 44 of the heat sink 33 to cool the heat generating device such as the power supply unit 27. As described above, since a cool wind absorbed from the open air 42 sent from the second cooling fan 35 enters into the fins 44 of the heat sink 33 with a proper inclination angle, the fins 44 are cooled by a stronger cooling wind and hence a cooling effect for cooling the heat sink 33 can be enhanced.

The arrangement of the HDD drive unit 29 will be described next with reference to FIGS. 7 and 8. FIG. 8 is a cross-sectional view taken along the line VIII—VIII in FIG. 7. As illustrated, the HDD drive unit 29 is fixed to boss portions 46, formed by chassis contraction, on the chassis 21 and a sub-chassis 47 fixed to the left side plate of the chassis 21 bent in a U-like shape.

The sub-chassis 47 has a heat-radiation through-hole 48 of substantially dome-like shape for exhausting air formed at substantially the central portion of a substantially rectangular solid-like major surface 47 thereof. Left and right ends of the major surface 47 are bent in the upper and lower direction so as to become perpendicular to each other to form an attachment leg portion 47 a and an attachment member 47 b. The attachment leg portion 47 a is fixed to the chassis 21 through the boss portion 46, formed by chassis contraction, and the attachment member 47 b is fixed to the right side surface portion of the chassis 21 which is bent in a U-like shape.

As shown in FIG. 8 which is a cross-sectional view taken along the line VIII—VIII in FIG. 7, the HDD drive unit 29 is composed of a disk drive unit 51 covered with a metal box-like inner casing 50 serving as an enclosure, a pickup head 52, the HDD 45 including input and output shroud groups (see FIG. 7) and the like, a shock-absorbing device (noise absorption member) in which the inner casing 50 of the HDD 45 is enclosed with a foam resin sheet 53 with cushion property such as polyurethane, an elastic rubber and a foam soft synthetic resin to form a shock-absorbing and noise-insulation shock-absorbing device and an outer casing 54 serving as a noise insulation box.

The upper, lower, right and left plates and the back plate of the inner casing 50 of the HDD 45 are wrapped with the foam resin sheet 53 made of polyurethane for use in shock-absorbing and noise insulation and the inner casing 50 of the HDD 45 is further inserted into the noise insulation outer casing 54. A foam heat transmission sheet 55 is disposed on the upper plate (top) of the inner casing 50. More specifically, the foam heat transmission sheet 55 for transmitting heat accumulated within the HDD 45 and which is transmitted to the top of the inner casing 50 is attached to the side of the outer casing 54 so as to be brought in contact with a part of the top of the inner casing 50.

Further, electrically-conductive gaskets 56 made of a suitable material such as a foam metal mesh for preventing the HDD 45 from being broken by static electricity are fixed to the outer casing 54 or they are fixed to the left and right corner portions of the inner casing 50 of the HDD 45, thereby being electrically conducted with the inner casing 50 or the outer casing 54. In FIG. 8, reference numeral 57 denotes a thermoplastic or thermosetting film sheet having a slippery surface, such as a polyethylene or vinyl chloride thin film. A heat radiation sheet 66 a for radiating heat transmitted to the outer casing 54 is formed on the outer surface of the top 62 of the outer casing 54. Far-infrared rays radiated from this heat radiation film 66 a are radiated into a heat radiation sheet 66 b formed on the cover 24 of the recorder 20 located at the position spatially spaced apart from the top 62 of the outer casing 54. In this case, the heat radiation sheet 66 a radiates heat of far-infrared rays into the air and heat of the far-infrared rays radiated in the air is strongly absorbed by the same heat radiation heat 66 b formed on the cover 24 of the recorder 20. Accordingly, heat from the inner casing 50 of the HDD 45 is radiated from the far-infrared ray heat radiation sheet 66 a attached to the outer casing 54 by the far-infrared ray transmitting and receiving members composed of a pair of far-infrared ray heat radiation sheets 66 a and 66 b and absorbed by the heat radiation sheet 66 b attached to the inner surface of the cover 24. Heat raised at high temperature within the HDD 45 is radiated from the cover 24 comprising the heat radiation sheet portion. Although heat from the inner casing 50 can of course be radiated to the outside by the cover 24 without the heat radiation sheet 66 b formed on the side of the cover 24, when the heat radiation sheet 66 b is attached to the inner surface of the cover 24, heat radiated from the heat radiation sheet 66 a can be efficiently absorbed by the heat radiation sheet 66 b and therefore heat radiation effect can be enhanced.

A structure of the film sheet 57 for wrapping the inner casing 50 of the above-mentioned HDD 45, a method for attaching the foam resin sheet 53 and a method for mounting (inserting) the inner casing 50 wrapped with the foam resin sheet 53 into the outer casing 54 will be described with reference to FIGS. 9, 10 and 11.

Prior to describing the present invention with reference to FIG. 9, the present invention will be described with reference to FIG. 10. FIG. 10 is a perspective view showing an example of the film sheet 57. As shown in FIG. 10, the film sheet 57 made of a thin film synthetic resin such as polyethylene and vinyl chloride and which has a slippery surface is cut in the form of a substantially rectangular solid. An upper sheet 57 a which contacts with the top of the HDD 45 is composed of front, back, left and right folding sheet members 57F, 57B, 57L and 57R which are brought in contact with the front, back, left and right plates of the HDD 45 and thereby folded along folding lines 57 h. A substantially square-shaped lower sheet 57 b, continued from the folding sheet member 57B to contact with the back side of the inner casing 50, has a rectangular radiation opening 57 f formed thereon to radiate heat from the HDD 45. At the same time, the lower sheet 57 b has a tongue-like pull-out member 57 g punched out along the folding line 57 h.

The upper sheet 57 a has a square electrically conductive through-hole 57 e formed at substantially the central position thereof and, a substantially square heat transmission sheet 55 attached to the inner surface of the outer casing 54 is brought in contact with the top of the inner casing 50 through this electrically-conductive through-hole 57 e. Also, the upper sheet 57 a has front, back, right and left rectangular ground through-holes 57 c, 57 d formed on the front, back, right and left portions thereof. Four substantially square electrically-conductive gaskets 56 attached to the inner surface of the outer casing 54 are brought in contact with the top of the inner casing 50 through the ground through-holes 57 c, 57 d. That is, the film sheet 57 for use with the present invention may be cut in the shape which results from adding a cross-like shape portion having left, right, front and back folding areas and a rectangular shape from the original of the film sheet.

A method of attaching the foam resin sheet 53 to the film sheet 57 will be described with reference to FIG. 11. As shown in FIG. 11, the substantially rectangular foam resin sheet 53 a is attached to the film sheet 57 from the back side of the lower sheet 57 b. The foam resin sheets 53 b of similar shape are attached to the left and right folding sheet members 57L, 57R, and further substantially L-like foam resin sheets 53 c and which have recesses corresponding to the rectangular ground holes 57 c, 57 d are attached to the upper sheet 57 a. The L-like short side portion of one foam resin sheet 53 c is attached to the front sheet folding member 57F and the long side portion thereof is attached to the left side surface of the upper sheet 57 a. The L-like short side portion of the other foam resin sheet 53 d is attached to the back sheet folding member 57B and the long side portion thereof is attached to the right side surface of the upper sheet 57 a.

FIG. 9 is an exploded perspective view used to explain the assembled state presented when the HDD 45 is mounted on the outer casing 54 of the HDD drive unit 29. A method of mounting the HDD 45 wrapped with the wrapping body 59 in which the foam resin sheet 53 is attached to the film sheet 57 from the back side of the outer casing 54 onto the outer casing 54 will be described below. The top 60 of the box-like enclosure comprising the inner casing 50 of the HDD 45 is provided in the lower side in FIG. 9 and the upper side of the top 60 is not provided with a metal bottom plate so that a printed circuit board and the like are made open. The disk drive unit 51, the pickup head 52 and the like are disposed in the inside of the HDD 45 as has been described before in detail with reference to FIG. 8. In FIG. 9, reference numeral 49 denotes input and output connection shroud group of the HDD 45.

The foam resin sheets 53 a, 53 b, 53 c and 53 d are attached to the film sheet 57, described with reference to FIG. 10, to thereby form the wrapping body 59. The top 60 of the HDD 45 is mounted on the foam resin sheets 53 c and 53 d of the upper sheet 57 a of the film sheet 57 comprising this wrapping body 59. Left, right, front and back folding members 57L, 57R, 57F and 57B are folded so that they may be erected, respectively. The left, right, front and back side plates of the inner casing 50 of the HDD 45 are wrapped with the elastic foam resin sheets 53 b, 53 c and 53 d which are excellent in vibration isolation property and noise insulation property and the lower sheet 57 b is mounted on the back side of the HDD 45, whereby the back side of the HDD 45 is covered with the foam resin sheet 53 a through the film sheet 57.

The HDD 45 wrapped with the wrapping body 59 in this manner is inserted into the outer casing 54. As shown in FIG. 9, the outer casing 54 is substantially a box made of a metal plate such as an aluminum plate. Left and right side plates 54L, 54R and the end portion of the back side plate 54B of the outer casing 54 are bent in the direction perpendicular to the top 62 to thereby form a fixed hole 61 to fix the outer casing 54 to the sub-chassis 47. Also, the front side plate 54F of the outer casing 54 is bent slightly so as to expose the connection shroud group 49 of the HDD 45 to the outside. An elastic heat conductive sheet 55 of a substantially rectangular shape with excellent heat conduction property and of which size is smaller than the rectangular electrically-conductive hole 57 e bored on the film sheet 57 is bonded to the central position of the inside of the top 62 of the outer casing 54. A non-silicon-based hyper soft heat radiation material (No. 5505S) manufactured by 3M CORPORATION, for example, can be used as this heat conductive sheet 55. This hyper soft heat radiation material is made of a thin base film on which a heat conductive acrylic elastomer is formed.

The elastic electrically-conductive gaskets 56 of substantially rectangular shape with excellent electrically-conductive property and which are smaller than the rectangular ground holes 57 d, 57 c bored on the film sheet 57 are bonded to left, right, front and back positions of the inside of the top 62 of the outer casing 54. A soft high seal gasket (SHSG) manufactured by KITAGAWA INDUSTRIES CO., LTD., for example, can be used as this electrically-conductive gasket 56. This SHSG is made of a foam resin with an electrically-conductive mesh mixed thereto and is able to keep electrically-conductive property under relatively low compression force.

An insertion method required when the sub-assembly wrapping body 65 in the sub-assembly state in which the above-mentioned HDD 45 is wrapped with the wrapping body 59 is inserted into the outer casing 54 will be described with reference to FIGS. 12A, 12B and 12C. FIG. 12B is a cross-sectional side view showing the state in which the sub-assembly wrapping body 65 is cut along the direction perpendicular to the long side of the outer casing 54. A short side inside dimension L2, a long side inside dimension (not shown) and an inside height H2 of the outer casing 54 are smaller than a short side outer dimension L1, a long side outer dimension (not shown) and an outside height H1 of the sub-assembly wrapping body 65. The reason for this is that the volume of the sub-assembly wrapping body 65 is increased by the amount corresponding to the thicknesses produced when the foam resin sheets 53 a, 53 b, 53 c and 53 d attached to the film sheet 57 can be contracted.

The heat radiation sheet 66 a is attached to the surface of the top 62 of the outer casing 54 as has been described before with reference to FIG. 8. FIG. 12C is a schematic diagram showing a portion D in FIG. 12B in an enlarged-scale. As shown in FIG. 12C, a far-infrared ray transmitting and receiving member made of ceramic for radiating or absorbing far-infrared rays, for example, manufactured by OKI ELECTRIC INDUSTRY COMPANY LIMITED under the trade name of “MAZUHARU ICHIBAN” (registered trademark) can be used as this heat radiation sheet 66 a formed on a bonding sheet 67 comprising the bonding layer. Although a hard type far-infrared ray transmitting and receiving member in which ceramic is coated on a base such as aluminum or a far-infrared ray transmitting and receiving member using a flexible film as a base thereof is commercially available on the market, the present invention is not limited thereto and a far-infrared ray transmitting and receiving material such as ceramic may be directly coated on the outer surface of the top 62 of the outer casing 54 or the inner surface of the cover 24. Also, the outer casing 54 may be processed as a box from a metal material such as aluminum coated with the far-infrared ray transmitting and receiving member.

Accordingly, when the sub-assembly wrapping body 65 is pushed into the outer casing 54 with pressure as shown by an open arrow C in FIG. 12B, the foam resin sheets 53 b, 53 c and 53 d attached to the film sheet 57 are crushed and the surface of the film sheet 57 is slippery so that the sub-assembly wrapping body 65 can be smoothly inserted into the outer casing 54.

The sub-assembly wrapping body 65 incorporating therein the HDD 45 inserted into the outer casing 54 can be strongly held within the outer casing 54 by the swollen (expanded) foam resin sheets 53 b, 53 c and 53 d. A method of removing the sub-assembly wrapping body 65 inserted into the outer casing 54 as described above from the outer casing 54 with ease will be described with reference to FIGS. 13A, 13B and FIG. 14.

In FIGS. 13A, 13B and FIG. 14, FIGS. 13A and 13B are perspective views showing, in a partly cross-sectional fashion, the state in which the sub-assembly wrapping body 65 is inserted into the outer casing 54, and FIG. 14 is a cross-sectional side view showing the state in which the sub-assembly wrapping body 65 is pulled out of the outer casing 54. When the sub-assembly wrapping body 65 incorporating therein the HDD 45 loaded into the outer casing 54 is pulled out of the outer casing 54, since the tongue-like pull-out member 57 g formed on the film sheet 57 lies on the side of the back plate 54B of the outer casing 54 as shown in FIG. 13A, a user raises this tongue-like pull-out member 57 g with fingers as shown in FIG. 13B and lifts the pull-out member 57 g as shown by an open arrow E in FIG. 14, whereby the foam resin sheets 53 b, 53 c and 53 d attached to the wrapping body 59 are lifted while they are contracted by the front plate 54F and the left and right plates 54L, 54R. As a result, the user is able to pull out the sub-assembly wrapping body 65 from the outer casing 54 with ease.

The sub-assembly wrapping body 65 incorporating therein the HDD 45 as described above can be easily inserted into or removed from the outer casing 54 by using slippage on the slippery surface of the film sheet 57. While the top 62 of the sub-assembly wrapping body 65 is being directed upwards, the sub-assembly wrapping body 65 is fixed to the sub-chassis 47 through the foam resin sheet 53 a by suitable means such as screws as shown in FIG. 8. Accordingly, as shown in FIG. 8, the sub-assembly wrapping body 65 becomes able to use the foam resin sheet 53 a as the shock-absorbing member relative to the sub-chassis 47 so that the HDD 45 can be insulated from vibrations of the sub-chassis 47.

Next, a method of controlling the first and second cooling fans 32 and 35 provided within the chassis 21 of the recorder 20 shown in FIGS. 5 and 6 will be described with reference to a flowchart of FIG. 15. The CPU 34 shown in FIG. 5 executes control operations shown in the flowchart of FIG. 15. The two first and second cooling fans 32 and 35 are able to rotate at high speed (hereinafter referred to an “H rotation mode”) and at low speed (hereinafter referred to as an “L rotation mode”) selectively.

Referring to FIG. 15 in detail, when a power switch is turned on, the CPU 34 starts controlling the two cooling fans 32 and 35. Then, control goes to a first step ST1, whereat the power switches of the first and second cooling fans 32 and 35 are turned off. In the first step ST1, the first and second cooling fans 32 and 35 are placed in the stop mode for a predetermined time period of T0, for example, 5 minutes in order to dampen noise following turning on of the power switch.

Then, control goes to the next second decision step ST2, whereat it is determined by the CPU 34, which has been described with reference to FIG. 5, whether or not a temperature detected by the open air detection sensor 38 is higher than a predetermined temperature T1° C. (for example, 55° C.). If the temperature detected by the open air detection sensor 38 is higher than the predetermined temperature T1° C., then it is determined that the open air detection sensor 38 is de-energized. Thus, if the detected temperature is higher than the predetermined temperature T1° C. as represented by a YES at the second decision step ST2, then control goes to a 14th step ST14, whereat the CPU 34 executes emergency processing to de-energize the recorder 20. In the emergency processing at the 14th step ST14, the power switch of the power supply unit 27 is turned off and the power switch can be prevented from being turned off even when the power supply unit 27 is again energized so long as the emergency processing is canceled. If the temperature detected by the open air detection sensor 38 is lower than the predetermined temperature T1° C. as represented by a NO at the second decision step ST2, then control goes to a third decision step ST3.

It is determined by the CPU 34 at the third detection step ST3 whether or not a temperature detected by the open air detection sensor 38 is higher than a predetermined temperature T2° C. (for example, 35° C.). If the temperature detected by the open air detection sensor 38 is higher than the predetermined temperature T2° C. as represented by a YES at the third detection step ST3, then control goes to a tenth step ST10, whereat the CPU 34 executes high speed rotation setting processing to allow the first and second cooling fans 32 and 35 to rotate at high speed (H rotation mode). If the detected temperature is not higher than the predetermined temperature T2° C. as represented by a NO at the third decision step ST3, then the two cooling fans 32 and 35 are de-energized respectively. More specifically, if the temperature detected by the open air detection sensor 38 is not higher than the predetermined temperature T2° C. as represented by a NO at the third decision step ST3, then control goes to a fourth decision step ST4. In the fourth decision step ST4, it is determined by the CPU 34 whether or not a temperature detected by the CPU sensor 39 added to the CPU 34 is higher than a predetermined temperature T3° C. (for example, 60° C.). If the temperature detected by the CPU sensor 39 is higher than the predetermined temperature T3° C. as represented by a YES at the fourth decision step ST4, then control goes to the tenth step ST10, whereat the CPU 34 executes high speed rotation setting processing to allow the first and second cooling fans 32 and 35 to rotate at high speed (H rotation mode). If on the other hand the detected temperature is not higher than the predetermined temperature T3° C. as represented by a NO at the decision step ST4, then control goes to a fifth decision step ST5.

It is determined at the fifth decision step ST5 by the CPU 34 whether or not the predetermined time T0 (for example, 5 minutes) passed. If the predetermined time T0 does not pass as represented by a NO at the fifth decision step ST5, then control goes back to the second decision step ST2. If on the other hand the predetermined time T0 passed as represented by a YES at the fifth decision step ST5, then control goes to a sixth step ST6.

In the sixth step ST6, the CPU 34 sets the first and second cooling fans 32 and 35 to the L rotation state, respectively so that the first and second cooling fans 32 and 35 can be rotated at low speed.

Then, control goes to a seventh decision step ST7, whereat it is determined by the CPU 34 whether or not a temperature detected by the open air detection sensor 38 is higher than the predetermined temperature T1° C. If the detected temperature is higher than the predetermined temperature T1° C. as represented by a YES at the 7th decision step ST7, then the open air detection sensor 38 is de-energized and control goes to the 14th step ST14, whereat the CPU 34 executes the emergency processing to turn off the power supply. If on the other hand the detected temperature is not higher than the predetermined temperature T1° C. as represented by a NO at the 7th decision step ST7, then control goes to the next 8th step ST8.

It is determined at the 8th decision step ST8 by the CPU 34 whether or not a temperature detected by the open air detection sensor 38 is higher than the predetermined temperature T2° C. If the detected temperature is higher than the predetermined temperature T2° C. as represented by a YES at the 8th decision step ST8, then control goes to the 10th step ST10, whereat the first and second cooling fans 32 and 35 are switched to the H rotation state, that is, the first and second cooling fans 32 and 35 can rotate at high speed. If on the other hand the detected temperature is not higher than the predetermined temperature T2° C. as represented by NO at the 8th decision step ST8, then control goes to the next 9th decision step ST9. It is determined at the 9th decision step ST9 by the CPU 34 whether or not a temperature detected by the CPU sensor 39 is higher than the predetermined temperature T3° C. If the detected temperature is higher than the predetermined temperature T3° C. as represented by a YES at the 9th decision step ST9, then control goes to the 10th step ST10, whereat the first and second cooling fans 32 and 35 are switched to the H rotation mode, that is, the first and second cooling fans 32 and 35 can rotate at high speed. If on the other hand the detected temperature is not higher than the predetermined temperature T3° C., then control goes back to the 7th step ST7, and the 7th decision step ST7 to the 9th decision step ST9 are repeated.

In the 10th step ST10, the first and second cooling fans 32 and 35 are rotated at high speed in the H rotation mode as described above. Control goes to the next 11th decision step ST11, whereat it is determined by the CPU 34 whether or not a temperature detected by the open air detection sensor 38 is higher than the predetermined temperature T1° C. If the detected temperature is higher than the predetermined temperature T1° C. as represented by a YES at the 11th decision step ST11, then the open air detection sensor 38 is de-energized and control goes to the 14th step ST14, whereat the CPU 34 executes the emergency processing to de-energize the power supply. If the detected temperature is not higher than the predetermined temperature T1° C. as represented by a NO at the 11th decision step ST11, then control goes to the next 12th decision step ST12. It is determined at the 12th decision step ST12 by the CPU 34 whether or not a temperature detected by the open air detection sensor 38 is higher than a predetermined temperature T4° C. (for example, 32° C.).

If the detected temperature is higher than the predetermined temperature T4° C. as represented by a YES at the 12th decision step ST12, then control goes back to the sixth step ST6, whereat the first and second cooling fans 32 and 35 are rotated at low speed (L rotation mode). If on the other hand the detected temperature is not higher than the predetermined temperature T4° C. as represented by a NO at the 12th decision step ST12, then control goes to the next 13th decision step ST13. It is determined at the 13th decision step ST13 by the CPU 34 whether or not a temperature detected by the CPU sensor 39 is lower than a predetermined temperature T5° C. If the detected temperature is higher than the predetermined temperature T5° C. as represented by a NO at the 13th decision step ST13, then control goes back to the 11th decision step ST11 and the 11th decision step ST11 to the 13th decision step ST13 are repeated. If the detected temperature is lower than the predetermined temperature T5° C. as represented by a YES at the 13th decision step ST13, then control goes back to the sixth step ST6, whereat the first and second cooling fans 32 and 35 are both rotated at low speed (L rotation mode).

Specifically, according to the present invention, when the power supply is set to the initial state, the two first and second cooling fans 32 and 35 are placed in the de-energized state for about 5 minutes in order to dump a noise. If the temperature detected by the open air detection sensor 38 is lower than the predetermined temperature T1° C., then the first and second cooling fans 32 and 35 are placed in the de-energized state. If on the other hand the above temperature detected by the open air detection sensor 38 is higher than the predetermined temperature T1° C., then the first and second cooling fans 32 and 35 are rotated at high speed (H rotation mode). If the temperature detected by the open air detection sensor 38 is lower than the predetermined temperature T1° C. and a predetermined time T0 (5 minutes) passed, then the first and second cooling fans 32 and 35 are rotated at low speed (L rotation mode). If the temperature detected by the open air detection sensor 38 becomes higher than the predetermined temperature T2° C. and the open air detection sensor 38 is de-energized, then control of the CPU 34 goes to the emergency processing to de-energize the power supply. If the temperature detected by the CPU sensor 39 becomes higher than the predetermined temperature T3° C., then the first and second cooling fans 32 and 35 are rotated at high speed (H rotation mode).

Also, if the temperature detected by the open air detection sensor 38 becomes higher than the predetermined temperature T1° C., then the first and second cooling fans 32 and 35 are rotated at high speed (H rotation mode). If the temperature detected by the open air detection sensor 38 becomes higher than the predetermined temperature T2° C. and the open air detection sensor 38 is de-energized, then control of the CPU 34 goes to the emergency processing at the step ST14 to de-energize the power supply. If the temperature detected by the CPU sensor 39 becomes higher than the predetermined temperature T3° C., then the first and second cooling fans 32 and 35 are rotated at high speed (H rotation mode).

Further, if the temperature detected by the open air detection sensor 38 becomes lower than the predetermined temperature T4° C., then the first and second cooling fans 32 and 35 are rotated at low speed (L rotation mode). If on the other hand the temperature detected by the open air detection sensor 38 becomes higher than the predetermined temperature T1° C. and the open air detection sensor 38 is de-energized, then control of the CPU 34 goes to the emergency processing at the step ST14 to de-energize the power supply. If the temperature detected by the CPU sensor 39 becomes lower than the predetermined temperature T5° C., then the first and second cooling fans 32 and 35 are rotated at low speed (L rotation mode).

According to the present invention, in the electronic apparatus in which a signal is recorded and/or reproduced by the hard disk drive and in which heat generated from the hard disk drive is transmitted to the heat transmission unit and introduced into the heat radiation unit and thereby radiated to the outside, the hard disk drive is attached to the fixed portion of the electronic apparatus through an elastic material and the heat radiation unit is attached to the fixed portion of the electronic apparatus without an elastic material. Also, the hard disk drive, the heat radiation unit and the heat transmission unit have far-infrared transmitting and receiving members formed on their surfaces so that heat is transmitted through two opposing surfaces distant from each other by a predetermined length. Thus, it is customary that the HDD is attached to the fixed portion such as the base of the electronic apparatus through the elastic material so that the HDD may be prevented from being directly shocked by vibrations. On the other hand, when the heat radiation unit is directly attached to the base, there is an advantage that heat is transmitted from the heat radiation unit to the base. However, when the heat radiation unit and the HDD are joined by means of a heat transmission member, vibration and shock of the fixed portion are directly transmitted to the HDD. Therefore, according to the arrangement of the present invention, that is, “heat is transmitted through the two opposing surfaces distant from each other by the predetermined length in which the far-infrared ray transmitting and receiving members are disposed”, there can be constructed an arrangement in which vibration and shock can be prevented from being transmitted to the hard disk drive although heat can be transmitted thereto.

A first embodiment according to the present invention will be described below.

In the sub-assembly wrapping body 65 that has been described so far with reference to FIG. 8, heat accumulated in the inner casing 50 of the HDD 45 is transmitted to the outer casing 54 through the heat conductive sheet 55. As shown in FIG. 16A, the far-infrared ray transmitting and receiving members composed of the heat radiation sheets 70 a, 70 b having arrangements similar to those of the heat radiation sheets 66 a, 66 b (see FIG. 8) are located at the opposing distant positions of the top 60 of the inner casing 50 of the HDD 45 and the top 62 of the outer casing 54 to thereby transmit accumulated heat from the top 60 of the inner casing 50 of the HDD 45 to the heat radiation sheet 70 b. Radiated heat is absorbed by the heat radiation sheet 70 a disposed on the inner surface of the top 62 of the outer casing 54, and heat radiated to the outer casing 54 is radiated from the cover 24 through the far-infrared ray transmitting and receiving members composed of the heat radiation sheet 66 b and the heat radiation sheet 66 a disposed on the cover 24. In FIGS. 16A and 16B, elements and parts identical to those of FIG. 8 are denoted by identical reference numerals and therefore need not be described.

FIG. 16B shows a further arrangement of the present invention. As shown in FIG. 16B, the heat radiation sheets 70 a, 70 b similar to those of FIGS. 8 and 16A are used to radiate heat accumulated in the HDD 45 to the heat sink 73 provided on the sub-chassis 47.

As shown in FIG. 16B, the HDD 45 has the vibration isolating structure relative to the sub-chassis 47 by the shock absorbing device such as the rubber leg portions 73, and the inner wall of the outer casing 45 is covered with the foam resin sheet 53 to thereby dump a noise and to isolate a noise. A metal heat transmission plate 72 of a substantially square shape is located at the position at which it is distant from the ceramic heat radiation plate 70 b formed on the top 60 of the HDD 45 in an opposing fashion. A far-infrared ray transmitting and receiving member formed of the heat radiation sheet 70 a is attached to the position at which the heat transmission plate 72 and the heat radiation sheet 70 b are opposed to each other. One end of the heat transmission plate 72 is fixed to the opposite side of the fins of the heat sink 71 and it is projected from the through-hole 74 bored on the outer casing 54. Accordingly, heat from the HDD 45 is radiated from the heat radiation sheet 70 b to the space, it is absorbed by the heat radiation sheet 70 a of the heat transmission plate 72, it is transmitted to the heat transmission plate 72 and it is further radiated through the heat transmission plate 72 from the heat sink 71 to the air.

According to the HDD 45 having the arrangement shown in FIGS. 16A and 16B, since accumulated heat from the HDD 45 or the outer casing 54 is completely isolated from the cover 24 serving as the heat radiation body and the heat sink 71, even when shocks and vibrations are applied to these heat radiation bodies, shocks and vibrations can be prevented from being transmitted to the HDD 45 and hence the HDD 45 can become more reliable.

A second embodiment of the present invention will be described below.

An example of other arrangement of the film sheet 57 that has been described so far with reference to FIG. 10 will be described with reference to FIG. 17. In FIG. 17, elements and parts identical to those of FIG. 10 are denoted by identical reference numerals and therefore need not be described. In the arrangement shown in FIG. 17, dome-like tongue portions 76L, 76R, 76F and square folding members 77 serving as the fastening margins of the front and back folding sheet members 57F, 57B are formed on the left folding sheet member 57L, the right folding sheet member 57R and the front folding sheet member 57F of the film sheet 57. Upon assembly, the tongue portions 76L, 76R, 76F are inserted into groove holes 78 formed on the lower sheet 57 b, and in the state in which the wrapping body 59 or the sub-assembly wrapping body 65 is assembled, the film sheet 57 can be formed as an inner box type. According to this arrangement, the sub-assembly wrapping body 65 can be mounted on the outer casing 54 more easily.

While the recorder including the HDD or the DVD has been described so far as the above-described electronic apparatus, the present invention is not limited thereto and the present invention can be applied to various kinds of apparatuses and electronic apparatuses, which generate heat, such as a disk recording and reproducing apparatus for recording and reproducing disks such as a CD (compact disc) and a CD-ROM (CD-read only memory) and recording and reproducing apparatus using a tape as a recording medium such as a VTR (video tape recorder) and a tape recorder.

According to the above-mentioned HDD and electronic apparatus of the present invention, there can be obtained the HDD and the electronic apparatus in which the HDD can be protected from being shocked when the shock is applied the electronic apparatus and the heat radiation means of the HDD from the outside.

According to the electronic apparatus and the HDD of the present invention, there can be obtained the electronic apparatus and the HDD in which heat generated from the HDD can be efficiently radiated and a seek noise generated when the pickup head within the HDD frequently seeks a target track can be decreased so that reliability of hard disk function can be maintained.

Having described preferred embodiments of the invention with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments and that various changes and modifications could be effected therein by one skilled in the art without departing from the spirit or scope of the invention as defined in the appended claims. 

1. An electronic apparatus, comprising: a hard disk drive for recording and/or reproducing a signal; a first heat radiation sheet for receiving heat generated by said hard disk drive and for radiating the received heat; and a second heat radiation sheet for absorbing heat radiated by said first heat radiation sheet and for radiating the absorbed heat; said hard disk drive being attached to a fixed portion of said electronic apparatus through an elastic material selectively arranged on said hard disk drive, said second heat radiation sheet being attached to an inner surface of a cover of said electronic apparatus, said first heat radiation sheet being attached to an outer surface of an outer casing which houses said hard disk drive, said first and second heat radiation sheets radiating far-infrared rays and being separated from each other by a predetermined distance.
 2. The electronic apparatus according to claim 1, wherein said fixed portion includes a chassis, said hard disk drive being housed within said outer casing through at least one of a noise insulation member and a vibration isolation member, the outer casing being secured to the chassis, and the heat from said hard disk drive is transmitted through said outer casing and the transmitted heat is then radiated to said first and second heat radiation sheets.
 3. The electronic apparatus according to claim 1 or 2, wherein said first and second heat radiation sheets are each selected from the group consisting of ceramic sheets and coatings of a ceramic paint.
 4. The electronic apparatus according to claim 1 or 2, further comprising a foam heat transmission sheet, the heat generated by said disk drive being transmitted to said first heat radiation sheet through said foam heat transmission sheet.
 5. A hard disk drive housing apparatus comprising: a box-shaped outer casing in which a hard disk drive is housed; at least one of a noise insulation member and a vibration isolation member arranged between said hard disk drive and an inner surface of said outer casing; a chassis for holding said box-shaped outer casing and said hard disk drive; a shock-absorbing member arranged between said hard disk drive and a surface of said chassis; a cover for covering said chassis; a heat transmission sheet disposed between a top surface of said hard disk drive and the inner surface of said outer casing; a first heat radiation sheet disposed on an outer surface of said box-shaped outer casing; and a second heat radiation sheet disposed on an inner surface of said cover at a position opposing to and spaced apart from the outer surface of said box-shaped outer casing; whereby heat from said hard disk drive is transmitted to said box-shaped outer casing through said heat transmission sheet and heat from the outer casing is radiated by the first heat radiation sheet to the second heat radiation sheet.
 6. The hard disk drive housing apparatus according to claim 5, wherein the first and second heat radiation sheets are each selected from the group consisting of a ceramic sheet and a ceramic paint. 